Lazy-tong hinge device



M. E. TULL ETAL LAZY-TONG HINGE DEVICE Aug. 17, 1954 2 Sheets-Sheet 1 Filed March 28, 1950 INVENTORS MERLE E. TULL DICK A. MOON ATTORNEY Aug. 17, 1954 TULL ET AL 2,686,332

' LAZY-TONG HINGE DEVICE Filed March 28, 1950 2 Sheets-Sheet 2 AVE l g INVENTORS MERLE E. TULL DICK A. MOON Patented Aug. 17, 1954 UNITED STATES PATENT OFFICE LAZY -TONG HINGE DEVICE Merle E. Tull and Dick A. Moon, San Diego, Calif.

Application March 28, 1950, Serial No. 152,452

2 Claims.

Our invention relates to lazy-tong hinge devices, and its objects are to provide one or more extensible hinges for the connection of a table leaf with a table top to allow the leaf to be turned from vertical position below the table top to linear extension therewith without frictional contact of the moving parts exposing an unsightly gap therebetween; to provide an improved mounting for each hinge which will permit the same to be readily installed and operated without binding and without frictional contacts; to render the parts readily accessible for inspection, adjustment, removal, replacement and repair; and in general to provide a device which is simple and economical of construction, saving of labor and materials, efficient in action and of prolonged life and durability. These and other objects will appear from the drawings and as hereinafter more fully set forth and described.

Primarily our invention consists in a lazy-tong hinge for the swinging connection of a table leaf and table top, the pivotally connected links of which hinge are of single and double unit lengths, and which are mounted upon anchor brackets secured to said leaf and top so as effectually to prevent frictional contacts of the adjacent ends of the same, and to eliminate unsightly gaps therebetween.

Our invention further consists of other novel features of construction, and combinations and arrangements of parts, illustrated in the drawings and hereinafter more specifically described and claimed.

Attention is hereby directed to the drawings, illustrating a preferred form of our invention, in which similar numerals of designation refer to similar parts throughout the several views, and in which- Figure 1 is an isometric view of a lazy-tong hinge embodying our invention, showing the hinge in closed position and as attached to, a table top and table leaf, the upper end of the leaf being shown flush and closely abutting with the bottom of the table top adjacent to the end thereof;

Fig. 2 is a side elevation of the table top, table leaf, lazy-tong hinge, and anchoring brackets therefor shown in Fig. 1, showing the hinge in extended position, and the said top and leaf in linear extension, with adjacent ends flush and closely abutting.

Fig. 3 is a side elevation of the parts shown in Fig. 1, and

Fig. 4 is a geometric diagram for determining the dimensions of the parts of the hinge in relation to the thickness of the table top and leaf in extended position, where such thickness is known and the 2:1 ratio of the linkage and angular slopes of the anchoring brackets are constant; the numerals Pi and P2 serving respectively to identify the short and long bases of said anchoring brackets.

Referring to the drawings, our improved form of lazy-tong hinge is constructed of pivotally connected links 5, 8, l and 8, the ends of which links 5 and 1 are pivotally mounted upon the anchoring bracket 9, and the ends of which links 6 and 8 are pivotally mounted upon the anchoring bracket It; the bracket 9 being secured by screws to the bottom of the table top l2, and the bracket It) being secured by screws to the bottom of the leaf l4.

The anchoring brackets 9 and II) are similar in construction differing only in length and angular slope of their outwardly extending parts. Each bracket is made of a pair of angle irons of conforming shape and dimensions and spaced in exact parallel relation; the flat bases PI and P2 of which are secured by screws to the table top or leaf as aforesaid, and the outer edges of the outwardly extending flanges of which are straight and disposed at a predetermined angle for the purpose shortly to be described.

As shown, each of the said links is preferably formed of three flat strips of metal of the same size and positioned in spaced parallel relation, one end of each central strip being interposed in the space between the flanges of one of said brackets, and the corresponding ends of the outer strips straddling the parts of the flanges adjacent thereto; all of said ends being pivotally connected to said flanges at said adjacent parts by a tubular rivet or pin passing through openings provided therefor in said ends and flanges. Thus, the strips of the link 5 at their inner ends are pivotally secured to the heels l5, of the flanges of the bracket 9 by the tubular rivet l6, and at their outer ends are similarly secured to the outer ends of the strips of the link 6 by the tubular rivet H; the inner ends of the strips of the link 6 are pivotally secured to the toes l8, of the flanges of the bracket ID by the tubular rivet IS; the inner ends of the strips of the link i are pivotally secured to the toes 20, of the flanges of the bracket 9 by the tubular rivet 2i the central portion of the strips of the link I is pivotally secured to the central portion of the strips of the link 6 by the tubular rivet '22; the outer ends of the strips of the link 1 are pivotally secured to the outer ends of the strips of the link 8 by the tubular rivet 23; and the inner ends of the strips of the link 8 are pivotally secured to the heels 24 of the flanges of the bracket II) by the tubular rivet 25.

As will be observed, the length of the links 6, I and 8, and the strips thereof is exactly the same, and the length of the link is exactly one half of each of the other links, also that the distance between the axes of the tubular rivets is in the ratio of 2 to 1 for the longer and shorter distances therebetween, the longer distance being double that of the shorter distance; and that accordingly the longer distance is equal and the same in each case as between the axes of rivets l'|-l9, 2l-23 and 2325, and the shorter distance is equal and the same in each case as between the axes of tubular rivets [6-41, |'I-22, l9-22, 2l 22 and 22- 23.

In order that the hinge may be constructed and installed to accommodate variable thicknesses of the table top and table leaf it is necessary to determine accurately the length of the links, positioning of the tubular rivets, and the location of the anchoring brackets. This may be accomplished by determining the lengths of the links, the distance from center to center of the axes of the rivets, while the 2 to 1 ratio of the links and the angles of the slopes from heel to toe of the brackets, remain constant for all sizes of hinges.

We accordingly, through considerable study and experimentation with working models, and reconstruction and positioning of the same and parts thereof, and actual trial thereof under working conditions, have determined that for constructing and setting up our lazy-tong hinge for different thicknesses of both table and leaf, the geometric diagram set forth in Fig. 4 may generally be followed. Thus, taking for example such thickness to be .8125 (that is {-3) of an inch, and represented by the letter t, and a: to be .20 (that is of an inch, then the distances apart center to center of the axes of the rivets as shown upon the said diagram may be represented and figured as follows:

all (distance of rivets l9-2 l =8.55a;=1.71 inch d2 (distance of rivets |9-2l from table and leaf) =1.25x=.25 inch d3 (distance of rivet 19 from abutting end of leaf) =2.65a:=.53 inch d4 (distance of rivet 2| from abutting end of table) =5.90r=1.18 inches Ll (distance of rivets |6Il, Iii-2|, |'I-22, I9-

22, 2|--22, 2223) =4.375a:=.875 inch L2 (distance of rivets l9-25, 2l-23, 23-25):

8.75:c=1.75 inches For angles (as shown in Fig. 4), take sine 01 to be .22857 and take sine 02 to be .11429. For

any other thickness of table and leaf, then by the proportion t:x=t1::c1, (t represents thickness, :1: distance between pivots, t1 the desired thickness, and 1:1 the required distance between pivots) the distances between rivets and positioning of the same may be similarly figured.

Thus for a thickness of one inch, the equation would be Upon the hinge being constructed and applied to the table top and leaf as shown in the drawings and in accordance with the dimensions and location of parts following the determinations above set forth, it will be found that when as shown in Fig. 2, the table top and leaf are in extended position the adjacent ends of such top and leaf will abut and form a snug and smooth joint, and when the leaf has been swung downwardly at right angles to the table to the position' shown in Fig. 3, the end of the leaf will abut against the bottom of the table and form a similar joint. Also it will be found that in raising or lowering the leaf and swinging the same upon the hinge between these two positions, there will be no contact of the adjacent parts, and at all times an unsightly gap will be avoided.

Our invention may be embodied in such other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment, as above set forth is therefore to be considered in all respects as illustrative and not restrictive, the scope of our invention being indicated by the appended claims rather than by the foregoing description, and all changes which may come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What we claim and desire to secure by Letters Patent is:

1. A lazy-tong hinge, comprising a set of lazytong links, a pair of brackets pivotally secured thereto, and means for mounting said brackets so secured to the undersides of a table top and table leaf of the same thickness near adjacent edges thereof to form a hinge therebetween adapted to permit downward angular movement of said leaf in respect to said table top from horizontal alignment therewith to right angular relationship thereto below; said links and brackets being cooperatively adapted to bring about and to secure abutting contact of the adjacent confronting ends of said table top and leaf when swung into horizontally aligned position, and to secure abutting contact of the top end of said leaf with the bottom of the table top when the leaf is swung below into right-angled position therewith.

2. The subject matter of claim 1, the set of lazy-tong links therein referred to being made up of four pivotally connected links, three of which are of the same length with equally spaced pivotal connections, and one of which is one half such length and provided with pivotal connections, with one of said brackets and with one of the other three links adjacent thereto.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 123,818 French Feb. 20, 1872 414,461 Towson Nov. 5, 1889 1,918,040 Kassick July 11, 1933 2,151,732 Boyle Mar. 28, 1939 2,329,293 Predit Sept. 14, 1943 2,355,542 Loftin Aug. 8, 1944 FOREIGN PATENTS Number Country Date 313,760 Italy Jan. 5, 1934 317,820 Italy May 23, 1934 537,879 France Mar. 10, 1922 828,436 France Feb. 14, 1938 

